Duratech chimney exterior feels hotter than it should... Design Styles, Chimneys and Finish Discuss Duratech chimney exterior feels hotter than it should... in the Pizza Oven Design and Installation forums; I have the stainless steel Dura-Vent 8'' x 36'' DuraTech Chimney Pipe (9606) on my igloo. Others have reported that ...

[sjmeff]

I have the stainless steel Dura-Vent 8'' x 36'' DuraTech Chimney Pipe (9606) on my igloo.

Others have reported that the outside of the chimney is just warm to the touch. That's true for the front side of my chimney, but the back side is too hot for me to touch for longer than about 1 second. I can't take the temperature with my laser thermometer because it reflects off (like pointing it in a mirror).

My primary concern is that this is going to be too hot for the acrylic stucco finish I'm planning for the exterior, which would surround the chimney.

For those who have this same chimney, is this usual? Is it indeed too hot for acrylic stucco?

Thanks,
Stephen

[david s]

If your oven is fairly new then it is probably still eliminating water. This will make it hotter to touch. Keep firing and the problem may go away. Don't put on the acrylic until you are 100% sure the oven is dry. This may take about 10 firings. The acrylic makes it waterproof and will simply lock moisture in as well as preventing it from entering.

[Les]

Originally Posted by sjmeff

My primary concern is that this is going to be too hot for the acrylic stucco finish I'm planning for the exterior, which would surround the chimney.

I may be misunderstanding your intent, but you were not planning to put stucco on top of the steel duratech, were you? To my limited knowledge, thats not a good mix.

Les...

[sjmeff]

If your oven is fairly new then it is probably still eliminating water. This will make it hotter to touch. Keep firing and the problem may go away.

Thanks for the suggestion, David. In addition to the 8 curing fires, I've now fired it two times for cooking. I'll keep firing it several more times to see if it gets cooler.

I may be misunderstanding your intent, but you were not planning to put stucco on top of the steel duratech, were you? To my limited knowledge, thats not a good mix.

I'm not planning to stucco it all the way up the chimney, just around where it exits the roof as others have done (such as TheBadger: PhotoPlog - Enclosure).

I'm drawn to acrylic stucco as that seems to be the choice for the exterior render, but the heat might be an issue. I'm planning to call Quikrete on Monday to ask, but was hoping to hear from others who have used the same setup.

I also thought, perhaps, that it might be an issue with my chimney (maybe the insulation was omitted?).

S

[david s]

I was also concerned about the stucco to flue contact, so I put a layer of vermicrete around the flue, then the stucco over that.

[Rastys]

Sjmeff,
I just replied to a similar problem at:

http://www.fornobravo.com/forum/f9/6...pipe-7831.html (6" or 8" chimney pipe)

Check it out for some additional ideas.
You are always going to get your flue hot, way too hot for a paint, especially acrylics.
You cold always put an outer flue over the other one and pack it with some superwool insulation.

Rasyts

[ThisOldGarageNJ]

I used the acrylic stucco on the oven, There are spots on the transition that get about 250 degrees next to my fire brick chimney, When I called quickrete they told me not too be concerned till about 300 degrees, I hope they are right, But I have been cooking since may and so far so good

Mark

[sjmeff]

Thanks, Mark. Having a number to work with is helpful (saves me a call to Quikrete).

I think the chimney is probably always below 300 degrees, but I'll check the next time I fire up the oven.

I see that Simpson makes a 3-walled chimney. It's pricey, but I may have considered that if I had known this would be an issue.

Cheers,
Stephen

[Les]

Stephen,

You can buy some inexpensive HVAC tubing at the box stores. Center it around your Duratech and dump in some vermiculite. I would think that will drop the temps enough to stucco.

Just my thoughts.

Les...

[ThisOldGarageNJ]

I agree with les, I built mine with Firebrick, But next time I would just use the sheet metal duct and perhaps build brick around it and insulate with vermicrete.... They make chimney liners like that now... even flexible ones... They fill the void with cement and vibrate the tube with a finishing sander to get the air out...

Mark